An air spring making use of elasticity of compressed air has conventionally been known. For example, Japanese Patent Laying-Open No. 2000-035075 describes one example of a conventional air spring. The air spring described in this document has a stopper 8 provided in an inner cylindrical member 4 and having a protrusion 8b and first and second surfaces 6a and 6b provided in an outer cylindrical member 6 in correspondence with protrusion 8b.
Japanese Patent Laying-Open No. 2012-017769 also describes another example of a conventional air spring. The air spring described in this publication has an upper stop member 5 made of rubber and provided on an outer cylindrical member 1 and a lower stop member 12 provided on an inner cylindrical member 2. Japanese Patent Laying-Open No. 2012-145135 describes yet another example of a conventional air spring. This air spring has an upper stopper 12 made of rubber and provided on an upper member 3 and a lower stopper 16 provided in a lower member 4.